Ian Schrager has spent nearly half a century inventing places people remember more vividly than the things they did inside them. With his late partner Steve Rubell, the Brooklyn-bred impresario compressed a cultural epoch into Studio 54’s 33-month original run — and then, improbably, did it again in a second industry. Morgans, which he opened in 1984 in New York, is generally credited with inventing the boutique hotel; the Royalton, the Paramount, the Delano and the Mondrian followed, and with them the ideas every design-conscious hotel on earth now takes for granted: the lobby as a social ecosystem rather than a waiting room, the bar as a…